Vacuum in veg tank
May 24, 2007 - 7:09pm
A recent development: a vacuum seems to be building in my GC veg tank. I can't open the filler port without a little (very careful) prying help from a screwdriver, and then I hear the whoosh of air going in and see the tank rise a bit as the vacuum seal is broken. Is there a pressure relief somewhere that I'm overlooking that may have gotten clogged or polymerized with veg oil? If so, what's the bext method for opening it?
Thanks for any advice.
Jim
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It's the only planet we have, folks; treat it kindly.
May 25, 2007 - 10:12am
#2
apparently this is a common issue with the GC cap. I had same problem. Take a 1/16" drill and put a hole in the middle of the circle in the red plastic top of the cap. go thru one layer. The bottom conical piece that roates has three holes already drilled in it and acts as a baffle to minimze oil splashing out the hole you just drilled. The little silver "bell" on top is suposed to be the pressure relief, but they get gummed with polymerized VO. Just drill the hole and poke all four (top and bottom) with a paper clip each time you fill up to be sure they don't get plugged up. I put a towel over my cap to soak up any oil that seeps out from hard cornering, acceleration, sudden stops, etc.
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sdeck
2003 Jetta TDI, GreaseCar kit, veg-therm std, TDIHeater, >20,000 veggie miles and counting!
"If you make it idiot proof, nature will make a better idiot"
May 25, 2007 - 1:11pm
#3
Hard Cornering???? Acceleration??? What do you drive??? a Rocket Chip?... I mean rocket SHIP.....
But seriously, I dont know if its related to this warmer weather I am having the same difficulty with the vent cap not venting. I am going to employ one of these fixes overt this weekend.
Lee
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Novelty+Economy+Environment= NEE.....
I am a Knight that says NEE
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NoName - 2002 Jetta TDI - Greasecar setup - RC2 - Rocki Mod
May 25, 2007 - 1:30pm
#4
The Jetta is a run-of-the-mill no-mod auto, but my other vehicle is a GMC Yukon XL (FlexFuel) so everything is relative. I did take the switchback road up to Estes Park a few days ago in the Jetta though. I could actually drive it since my wife was not with me ;-). A lot more fun than the SUV.
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sdeck
2003 Jetta TDI, GreaseCar kit, veg-therm std, TDIHeater, >20,000 veggie miles and counting!
"If you make it idiot proof, nature will make a better idiot"
May 25, 2007 - 9:31pm
#5
Just in case someone's counting folks with this problem --- me too.
Thanks for the ideas I'll do that before the next long trip. For me long trips are the only time it's been a serious issue (symptoms like a clogged filter), I guess because I'm filling up as much as I can possibly fit, and the tank is already hot. When I start half full and cold, I actually get positive pressure in there once it heats up and the air expands.
-KCL
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'02 Jetta, Greasecar Kit + Vegtherm
~19,000 grease miles
August 23, 2007 - 11:10pm
#6
I had this problem too. As a matter of fact I believe it was what killed my IP. I took the red cap completely apart, pulled off the little rubber disk that covers the vent holes and tossed it in the trash. Keep the silver vent cap finger tight only and keep a paper clip in the trunk. Every time I refill I take off the little cap, clean out the holes as well as the three on the bottom of the cap and all is well. No vacuum build up at all and no oil spills either.
August 23, 2007 - 11:42pm
#7
yea, what they said. Hard to keep that from happening, just drill it or clean it out periodically. You can also loosen a sender or hatch plate screw if necessary.
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MarkP
August 26, 2007 - 6:35pm
#8
I wrote a thread about this several months ago... here's a link to the original thread:
http://www.greasecar.com/forum_topicview.cfm?frmtopicID=9985
...and here is a copy of the latest entry - ultimately the solution to my vacuum problems...
After months of the problems I described earlier in this thread, I finally found the problem. One day while refilling my greasetank I decided to take a really good look at the tank cap - specifically the tank vent. I had previously drilled out the holes on the top of the vent, but that didn't really help. I finally found that there is a small plastic 'cover' or 'gasket' on the bottom of the vent that is designed to release if negative pressure builds in the tank. Well, that little bugger was absolutely STUCK shut and would not allow any air into the tank when vacuum was building. I simply stuck my fingernail in there, pried the thing down off the cap, and since that day the car has run flawlessly.
Just thought I would share in case anyone else is experiencing the same incredibly frustrating problems I was having.
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1991 350SD 222,000 miles B20/WVO GreaseCar
2001 VW Beetle TDI 66,000 miles B20/WVO GreaseCar
1994 Plymouth Grand Voyager 98,000 miles
For Jazz Saxophone enthusiasts - check out my website...
[url]www.RustyBlevins.com[/url]
August 26, 2007 - 11:08pm
#9
Yep, it's a problem that can lead to underfueling symptoms. I put a 90 degree barb fitting in the inspection cover and ran a hose high, then looped down to a small bottle. Works great...no more vacuum.
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95 Cummins 4x4 pushing 400k miles and running like new.
August 28, 2007 - 5:47pm
#10
that is exactly what I did, I used a glass beer bottle. The tall, thin shape, and the heat tolerate glass is a good fit. I have never had anything end up in the bottle. I did think that maybe I would try to route the hose to the exterior of the car, to cut down on smell?
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There should be a vent on the tank. If memory is correct its just a little pin size hole. A lof of people have made there own vent holes because that one clogs. basically if you have a drill and tap or a little hardware the ideal situation is to install a small barb connection on the tank somewhere and put a tube on it and run it somewhere out of the way and higher level then the tank (to prevent spilling). Basically the tank does not need a lot of air flow so the smaller the fitting you can find and smaller hose you can find the better.
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01 vw jetta TDI : RC II : VR6 Clutch
Vag-Com tool at home
Veg 04-06 now mixing into the HHO
Another good veg site
http://fryertofuel.hypermart.net/store/page6.html